05 April 2012


Mozilla Thunderbird's default display font size (not the e-mail text font) is rather small. This is the font used in the folder pane, message list pane, menus, and elsewhere in the user interface (UI). You can easily change it by downloading the Thunderbird add-on Theme Font & Size Changer. You can also use this add-on in Firefox. Once installed in Thunderbird, you will see the button in your Status Bar, or you can use the Tools menu.


I recently changed my e-mail programme to Mozilla Thunderbird, after more than 15 years of using Eudora. I'm quite happy with Mozilla Thunderbird so far, and have made two changes that make it easier for me. The first change was getting rid of the dash-dash-space entry that automatically appears above your signature.

You can change the configuration settings to append a signature without the dashes.
Open Mozilla Thunderbird.
Open the Tools menu.
Select Options, then select Advanced.
Select Config Editor.
A popup will appear warning you that making changes may void your warranty or affect the "security, stability and performance of this application."
Click the "I'll be careful, I promise!" button to continue.
Find the "mail.identity.default.suppress_signature_separator" entry and double-click it.
This will change the entry from "false" to "true" and change the entry to boldface type.
Close Config Editor, and you're done.

Making changes to the configuration files can cause problems. Avoid changing any of the other entries while you are editing the signature settings.


I often receive e-mails with attachments named winmail.dat which don't open, no matter what I try. The sender insists they have sent me the correct attachments, yet I only see the winmail.dat attachment and no others. If you have the same problem, a solution is available...

How to prevent winmail.dat attachments from being sent:
The culprit seems to usually be the sender who uses Outlook e-mails in Rich Text Format (RTF). The formatting commands are then included in the winmail.dat file. Usually Outlook may also pack other file attachments inside the winmail.dat file, which explains why the sender says they have sent me the correct attachments but I don't see them. By preventing Outlook from sending RTF e-mails, you solve the problem.

To prevent Outlook from attaching winmail.dat when you send an e-mail:
Select Tools > Options from the menu.
Go to the Mail Format tab.
Under Compose in this message format: make sure either HTML or Plain Text is selected.
Click Internet Format.
Make sure either Convert to Plain Text format or Convert to HTML format is selected under When sending Outlook Rich Text messages to Internet recipients, use this format:
Click OK.
Click OK again.

If after this, someone still receives winmail.dat attachments, you can reset the format for individual addresses:
Search for that contact in your Outlook Contacts.
Double-click the contact's e-mail address.
Alternatively, click on that contact's e-mail address with the right mouse button and select Outlook Properties from the menu.
Make sure either Let Outlook decide the best sending format or Send Plain Text only is selected under Internet format.
Click OK.

How to extract files from winmail.dat attachments without Outlook:
If you receive winmail.dat attachments with embedded files, you can extract them using a winmail.dat decoder. I recommend the free and easy-to-use Winmail Opener.